This invention relates to a motor vehicle suspension system of the type having a damper with a rotatable member providing different damping positions in different rotational positions, a motor to drive the rotatable member, a feedback apparatus for indicating the rotational position of the rotatable member and a control responsive to the feedback apparatus and other inputs for selecting a desired rotational position and controlling the motor to drive the rotatable element thereto. It particularly relates to such a system in which the rotatable member, motor and feedback apparatus are all included within the damper.
The prior art shows such a system in which each defined rotational position of the rotatable member is uniquely indicated by a digital signal generating feedback apparatus which outputs a binary digital signal on a pair of feedback lines to the control. The particular apparatus defines four rotational positions and encodes these positions on two feedback lines. The apparatus could clearly be extended to a system with eight rotational positions; but this would require three feedback lines to uniquely encode the eight positions in digital binary signals. The use of three feedback lines has certain disadvantages relative to a single feedback line: (1) three wires are more expensive than one; (2) three wires take up too much space within a damper; and (3) three wires are more likely to exhibit a poor connection than a single wire. These disadvantages are even greater if the system is extended to a greater number of rotational positions. It would be desirable to provide such a system using a feedback apparatus with a single feedback line or wire carrying the position feedback information.